![pci-e thunderbolt add in card pci-e thunderbolt add in card](https://53.cdn.ekm.net/ekmps/shops/itinstock/images/hp-nvidia-quadro-nvs-290-pci-e-x16-256mb-graphic-card-low-profile-460815-001-56304-p.jpg)
This is separate and devices generally need more MMIO_PREF space than regular MMIO space.
![pci-e thunderbolt add in card pci-e thunderbolt add in card](https://ae01.alicdn.com/kf/HTB1crdDSFXXXXcgXVXXq6xXFXXX0/PCI-E-X4-to-M-2-NVME-SSD-NGFF-Convert-Card-B-M-Key-Converter-Adapter.jpg)
For the first issue, the add-in cards have GPIO that, if bridged, will force power the Thunderbolt controller. Reserve a PCIe bus number for any hotplug device to be addedįortunately, both of these can be worked around without requiring the manufacturer to provide a BIOS update.Power on the Thunderbolt controller so Linux can recognize it.
![pci-e thunderbolt add in card pci-e thunderbolt add in card](https://i.ytimg.com/vi/SOeowRP7ma0/maxresdefault.jpg)
In particular, the BIOS needs to perform two functions: The issue here is that many motherboard BIOSes do not properly initialize the Thunderbolt controller and thus Linux cannot make use of them. These instructions were tested on Ubuntu 21.04 with Linux kernel 5.11 and are likely not applicable to older kernels (which were missing patches). There are many guides online for issues like these, but a lot of them are outdated, so hopefully, this is helpful for people encountering this issue in >= 2021.